Identification and Physiological Assays of Crustacean Hyperglycemic Hormones in the Japanese Spiny Lobster, Panulirus japonicus.

The Japanese spiny lobster Panulirus japonicus lives on rocky shores and is mainly distributed along the Pacific coast around Japan. Due to the high demand for it, the development of aquaculture systems and increasing its resource volume requires further expansive production. However, a major factor preventing the establishment of aquaculture technology for this lobster is the difficulty with rearing processes from larval to juvenile production. A recent study shed light on the molecular mechanisms underlying larval development from the perspective of physiological functions of endocrine factors such as molting hormones. However, physiological studies of P. japonicus are still lacking. In decapod crustaceans, the X-organ/sinus gland complex is a well-known endocrine system that secretes the crustacean hyperglycemic hormone (CHH)-superfamily peptides that regulate growth, molting, sexual maturation, reproduction, and change in body color. In this study, we identified two CHHs from the sinus glands of P. japonicus using reversed-phase high-performance liquid chromatography in order to elucidate their physiological function for the first time.

Revision of the 'Acanthephyra purpurea' species complex (Crustacea: Decapoda), with an emphasis on species diversification in the Atlantic.

We inventoried all nine species of the 'Acanthephyra purpurea' complex, one of the most abundant and cosmopolitan group of mesopelagic shrimps. We used 119 specimens at hand and genetic data for 124 specimens from GenBank and BOLD. Phylogenetic analysis of four genes (COI, 16S, NaK, and enolase) showed that the 'Acanthephyra purpurea' complex is polyphyletic and encompasses two species groups, 'A. purpurea' (mostly Atlantic) and 'A. smithi' (Indo-West Pacific). The 'A. purpurea' species group consists of two major molecular clades A. pelagica and A. kingsleyi - A. purpurea - A. quadrispinosa. Molecular data suggest that hitherto accepted species A. acanthitelsonis, A. pelagica, and A. sica should be considered as synonyms. The Atlantic is inhabited by at least two cryptic genetic lineages of A. pelagica and A. quadrispinosa. Morphological analyses of qualitative and quantitative (900 measurements) characters resulted in a tabular key to species and in a finding of four evolutionary traits. Atlantic species showed various scenarios of diversification visible on mitochondrial gene level, nuclear gene level, and morphological level. We recorded and discussed similar phylogeographic trends in diversification and in distribution of genetic lineages within two different clades: A. pelagica and A. kingsleyi - A. purpurea - A. quadrispinosa.

Multiple scale assessment of habitat, landscape, and geographic-specific attributes driving decapod assemblages in Posidonia oceanica seagrass meadows.

Seagrass meadows are biodiversity hotspots for invertebrate species including decapods. Understanding the drivers of species abundance, richness and diversity of decapod assemblages is crucial for the conservation of such hotspots, but how drivers act across multiple spatial scales remains unexplored. Here we describe the decapod assemblages of Posidonia oceanica seagrass meadows and assess the influence of attributes from three increasing spatial scales (habitat, landscape, and geographical levels) on the assemblages' structure and composition, as well as the variability partitioning among each one of these levels. Overall, geographical level attributes (i.e., inlet aperture, confinement) affected the most the decapod assemblages, while we only found a modest contribution from habitat (e.g., detritus biomass, sediment organic matter) and landscape attributes (e.g., fragmentation). We suggest that decapod assemblages are driven by the interaction of multiple processes occurring at different scales and other highly stochastic phenomena such as larval dispersion and recruitment.

Exploring the preservation of a parasitic trace in decapod crustaceans using finite elements analysis.

The fossil record of parasitism is poorly understood, due largely to the scarcity of strong fossil evidence of parasites. Understanding the preservation potential for fossil parasitic evidence is critical to contextualizing the fossil record of parasitism. Here, we present the first use of X-ray computed tomography (CT) scanning and finite elements analysis (FEA) to analyze the impact of a parasite-induced fossil trace on host preservation. Four fossil and three modern decapod crustacean specimens with branchial swellings attributed to an epicaridean isopod parasite were CT scanned and examined with FEA to assess differences in the magnitude and distribution of stress between normal and swollen branchial chambers. The results of the FEA show highly localized stress peaks in reaction to point forces, with higher peak stress on the swollen branchial chamber for nearly all specimens and different forces applied, suggesting a possible shape-related decrease in the preservation potential of these parasitic swellings. Broader application of these methods as well as advances in the application of 3D data analysis in paleontology are critical to understanding the fossil record of parasitism and other poorly represented fossil groups.

Neurotoxic non-protein amino acids in commercially harvested Lobsters (Homarus americanus H. Milne-Edwards).

Cyanobacteria produce neurotoxic non-protein amino acids (NPAAs) that accumulate in ecosystems and food webs. American lobsters (Homarus americanus H. Milne-Edwards) are one of the most valuable seafood industries in Canada with exports valued at > $2 billion. Two previous studies have assessed the occurrence of ß-N-methylamino-L-alanine (BMAA) in a small number of lobster tissues but a complete study has not previously been undertaken. We measured NPAAs in eyeballs, brain, legs, claws, tails, and eggs of 4 lobsters per year for the 2021 and 2022 harvests. Our study included 4 male and 4 female lobsters. We detected BMAA and its isomers, N-(2-aminoethyl)glycine (AEG), 2,4-diaminobutyric acid (DAB) and ß-aminomethyl-L-alanine (BAMA) by a fully validated reverse phase chromatography-tandem mass spectrometry method. We quantified BMAA, DAB, AEG and BAMA in all of the lobster tissues. Our quantification data varied by individual lobster, sex and collection year. Significantly more BMAA was quantified in lobsters harvested in 2021 than 2022. Interestingly, more BAMA was quantified in lobsters harvested in 2022 than 2021. Monitoring of lobster harvests for cyanobacterial neurotoxins when harmful algal bloom events occur could mitigate risks to human health.

Integrating metagenomic and isolation strategies revealed high contamination of pathogenies and resistome in market shrimps.

This study employs a comprehensive approach combining metagenomic analysis and bacterial isolation to elucidate the microbial composition, antibiotic resistance genes (ARGs), and virulence factors (VFGs) present in shrimps from market and supermarket. Metagenomic analysis of shrimps revealed a dominance of Proteobacteria and Bacteroidetes with Firmicutes notably enriched in some samples. On the other hand, the dominant bacteria isolated included Citrobacter portucalensis, Escherichia coli, Salmonella enterica, Vibrio species and Klebsiella pneumonaie. Metagenomic analysis unveiled a diverse spectrum of 23 main types and 380 subtypes of ARGs in shrimp samples including many clinical significant ARGs such as blaKPC, blaNDM, mcr, tet(X4) etc. Genomic analysis of isolated bacterial strains identified 14 ARG types with 109 subtype genes, which complemented the metagenomic data. Genomic analysis also allowed us to identify a rich amount of MDR plasmids, which provided further insights into the dissemination of resistance genes in different species of bacteria in the same samples. Examination of VFGs and mobile genetic elements (MGEs) in both metagenomic and bacterial genomes revealed a complex landscape of factors contributing to bacterial virulence and genetic mobility. Potential co-occurrence patterns of ARGs and VFGs within human pathogenic bacteria underlined the intricate interplay between antibiotic resistance and virulence. In conclusion, this integrated analysis for the first time provides a comprehensive view and sheds new light on the potential hazards associated with shrimp products in the markets. The findings underscore the necessity of ongoing surveillance and intervention strategies to mitigate risks posed by antibiotic-resistant bacteria in the food supply chain using the novel comprehensive approaches.

Revision of the alvinocaridid shrimp genus Rimicaris Williams & Rona, 1986 (Decapoda: Caridea) with description of a new species from the Mariana Arc hydrothermal vents.

A new species of alvinocaridid shrimp is reported, from the Northwest Eifuku hydrothermal vent field at 16191667 m depth on the Mariana Arc. A comprehensive phylogenetic reconstruction of Alvinocarididae based on the mitochondrial cytochrome c oxidase subunit I (COI) gene including this new species reveals the paraphyly of the genus Rimicaris Williams & Rona, 1986 with four other generaAlvinocaridinides, Manuscaris, Opaepele, and Shinkaicarisnested within it. We re-examine material of these four problematic genera, and synonymise them under Rimicaris whose diagnosis has been amended, in order to maintain a monophyletic Rimicaris. Our new species, Rimicaris cambonae sp. nov. is genetically close to Rimicaris loihi (Williams & Dobbs, 1995) comb. nov. (previously Opaepele loihi) with which it co-occurs, but can be morphologically distinguished by the less elevated dorsal surface of the rostrum, this being devoid of a median carina, a stronger pterygostomial tooth on the carapace, and a blunt rather than acuminate proximolateral process on the antennular stylocerite. Species previously assigned to the above listed, synonymized genera are also discussed, with new material examined for three key species: R. loihi, R. acuminata, and R. leurokolos. Further, Alvinocaridinides formosa Komai & Chan, 2010 and Manuscaris liui Wang & Sha, 2016 are synonymized under Rimicaris leurokolos (Kikuchi & Hashimoto, 2000) comb. nov. and R. acuminata (Komai & Tsuchida, 2015) comb. nov., respectively. Revised diagnoses are presented for R. loihi, R. acuminata, and R. leurokolos. After the present revision revision, Rimicaris now consists of 15 species.

Non-marine Ostracoda (Crustacea) collected from pet shops and a hobbyists aquaria in Japan, including two new species.

Samples obtained from pet shops and a hobbyists aquaria in Japan have revealed a diverse non-marine ostracod fauna, consisting of 19 species, all contaminants of aquaria stocked with exotic fish, shrimps and/or aquatic plants. Of these, six are newly recorded for Japan, including two new species, belonging to the genera Pseudostrandesia and Tanycypris. Pseudostrandesia tenebrarum Smith & Ozawa, 2021, previously suspected to be an alien species in Japan, was again found in pet shops in this study. We also report living specimens of Potamocypris acuminata Fuhrmann & Goth, 2011, a species previously only known from Pleistocene deposits of Germany. The six new records for Japan reported herein are likely alien species as evidenced by previous records or congeneric species, with origins in East Asia, South East Asia, and the Americas. Thus, there are now seven ostracod species recognized as probable alien hitchhikers in the Japanese pet trade. This study highlights that the pet trade is a viable route for hitchhiking ostracod species to enter Japan, and such species have the potential to become invasive.

Reappraisal of Eiconaxius farreae Ortmann, 1891 and Eiconaxius mortenseni Sakai, 1992 (Decapoda: Axiidea: Axiidae), with description of a new species from Japan.

The sponge associated axiid shrimp Eiconaxius farreae Ortmann, 1891 was originally described based on specimens from Sagami Bay, central Japan. Morphological examination of many specimens of Eiconaxius collected from Sagami Bay and nearby areas, and genetic data from the mitochondrial COI and 16S rRNA genes have revealed that three species are represented. This finding led to a reappraisal of the identity of E. farreae and E. mortenseni Sakai, 1992, also originally described from Sagami Bay. It has been clarified that two species (E. farreae and an undescribed species) were mixed in the syntype material of E. farreae, and consequently, a lectotype of E. farreae is designated in the interest of nomenclatural stability. Here, E. farreae and E. mortenseni are redescribed, and the third species is described as new, E. reconditus. The new species is morphologically very similar to E. mortenseni. Differentiating characters among closely allied species are reassessed. Previous records of E. farreae are reviewed in light of the present findings.

Size dependent antipredator responses in a fish-shrimp mutualism.

For prey, taking refuge from predators has obvious fitness benefits but may also be costly by impinging on time and effort available for feeding or attracting mates. The antipredator responses of refuge-seeking animals are therefore predicted to vary strategically depending on how threatening they perceive the risk. To test this, we studied the impacts of a simulated predatory threat on the antipredator responses of wild sandy prawn-gobies (Ctenogobiops feroculus) that co-inhabit burrows with Alpheus shrimp (family Alpheidae) in a mutualistic relationship. We exposed goby-shrimp pairs, repeatedly on three separate occasions, to an approaching threat and measured the antipredator behaviours of both partners. We found that re-emerging from the burrow took longer in large compared to small fish. Moreover, quicker re-emergence by small-but not medium or large-sized gobies-was associated with an earlier flight from the approaching threat (i.e. when the threat was still further away). Finally, the goby and shrimp sharing a burrow were matched in body size and their risk-taking behaviour was highly dependent on one another. The findings contribute to our understanding of how an individual's phenotype and perception of danger relates to its risk-taking strategy, and how mutualistic partners can have similar risk sensitivities.

Evaluating conserved domains and motifs of decapod gonadotropin-releasing hormone G protein-coupled receptor superfamily.

G protein-coupled receptors (GPCRs) are an ancient family of signal transducers that are both abundant and consequential in metazoan endocrinology. The evolutionary history and function of the GPCRs of the decapod superfamilies of gonadotropin-releasing hormone (GnRH) are yet to be fully elucidated. As part of which, the use of traditional phylogenetics and the recycling of a diminutive set of mis-annotated databases has proven insufficient. To address this, we have collated and revised eight existing and three novel GPCR repertoires for GnRH of decapod species. We developed a novel bioinformatic workflow that included clustering analysis to capture likely GnRH receptor-like proteins, followed by phylogenetic analysis of the seven transmembrane-spanning domains. A high degree of conservation of the sequences and topology of the domains and motifs allowed the identification of species-specific variation (up to ~70%, especially in the extracellular loops) that is thought to be influential to ligand-binding and function. Given the key functional role of the DRY motif across GPCRs, the classification of receptors based on the variation of this motif can be universally applied to resolve cryptic GPCR families, as was achieved in this work. Our results contribute to the resolution of the evolutionary history of invertebrate GnRH receptors and inform the design of bioassays in their deorphanization and functional annotation.

Polychlorinated dibenzodioxins/furans and dioxin-like polychlorinated biphenyls in fish and crustaceans of a recreationally fished estuary, following targeted remediation.

Polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) are a suite of harmful chemicals (hereafter collectively referred to as 'dioxins'), and their emission into aquatic habitats leads to persistent contamination of sediments, aquatic food-webs, and seafoods. Quantifying contaminant levels in seafood species is important for the ongoing management of exposure risk by fishers, particularly after any remediation actions. We present dioxin concentrations in four seafood species (Yellowfin Bream Acanthopagrus australis, Sea Mullet Mugil cephalus, Eastern School Prawn Metapenaeus macleayi, and Eastern King Prawn Penaeus plebejus) in a recreationally fished estuary, in relation to a contaminated site that has undergone a remediation process, partially removing contaminated sediments (Homebush Bay, Port Jackson, New South Wales, Australia). Dioxin concentrations in these species were measured before (2005/6) and after (2015/16) remediation at a range of locations in and around the remediated site. Dioxin concentrations and congener profiles differed substantially among taxa, and concentrations were frequently higher than Australian screening criteria. The two prawn species showed evidence of a decline in dioxin concentrations after remediation, but the fish species only showed a declining dioxin concentration with distance from the contaminated site (not between periods). There were some minor changes in the congener profile for some species following remediation. While there was evidence for greatly reduced dioxin concentrations in prawn species following remediation, the complex patterns for fish were likely affected by environmental changes, species-specific and temporal changes in lipid content, and animal movement patterns. Future monitoring may aid interpretation of the patterns and modelling of exposure risk associated with seafood consumption into the future.

Pretreatment with Liposome-Encapsulated Shrimp Shell Extract Attenuated Neuronal Damage and Death in Aß1-42-Induced Memory Deficits in Rats.

The accumulation of amyloid-beta (Aß) peptides is a crucial factor in the neuronal degeneration of Alzheimer's disease (AD). The current study investigated the underlying neuroprotective mechanisms of shrimp shell extract (SSE) and liposome-encapsulated SSE (SSE/L) against Aß1-42-induced neuronal damage and death in rats. Intracerebroventricular infusion of Aß1-42 effectively induced memory decline, as observed in a reduction of the rat's discriminating ability in the novel object recognition and novel object location tasks. Oral pretreatment with 100 mg/kg of SSE demonstrated no preventive effect on the memory decline induced by Aß1-42 infusion. However, treatment with SSE/L 100 mg/kg BW effectively attenuated memory deficits in both behavioral assessments following two and four weeks after Aß1-42 infusion. Moreover, SSE/L exerted neuroprotective effects by reducing lipid peroxidation and increasing Nrf2/HO-1 expression. There was a significant decrease in Iba1 and GFAP (biomarkers of microglia and astrocyte activity, respectively), as well as a decrease in the levels of NF-κB expression and the inflammatory cytokines TNF-α and IL-6 in the cortical and hippocampal tissues. Treatment with SSE/L also reduced the pro-apoptotic proteins Bax and cleaved caspase-3 while raising the anti-apoptotic protein Bcl2. In addition, the beneficial effects of SSE/L were along with the effects of a positive control commercial astaxanthin (AST). The findings of this study indicated that SSE/L provided neuroprotective effects on Aß1-42-induced AD rats by ameliorating oxidative stress, neuroinflammation and apoptotic cell death. Therefore, SSE/L might be employed to prevent and mitigate Aß accumulation-induced neurotoxicity in AD.

Trace metals in commercial seafood products (canned, pickled and smoked): Comparison, exposure and health risk assessment.

This study used inductively coupled plasma and mass spectrometry, followed by microwave digestion, to assess the concentration of six trace metals (Cr, Ni, As, Cd, Hg, and Pb) in three canned products (tuna in oil [TIO], sardine in oil [SIO], and mackerel in oil [MIO]), two pickled products (prawn pickle [PP] and fish pickle [FP]), and one smoked product (masmin) collected from Tuticorin market, southern India. Trace metal (TM) levels in canned, pickled, and smoked fish varied from 0.01 to 1.48, 0.009 to 0.94, and 0.08 to 4.13 mg/kg, respectively. The concentration of TMs in the seafood was observed in the following order: As > Cr > Pb > Ni > Cd > Hg. Regarding their accumulation in the seafood products, masmin showed the highest levels followed by SIO, MIO, TIO, FP, and PP. The results revealed that smoked products showed higher TM concentrations, followed by canned and pickled products. The level of TMs in seafood products was below the maximum residue limit set by the European Commission (EC/1881/2006) and the Food Safety and Standards Authority of India (FSSAI). Risk assessment for consumer health implied that the evaluated target hazard quotient (THQ < 1), hazard index (HI < 1), and target cancer risk (TCR < 1.E-04) values did not exceed their guideline values and did not cause non-carcinogenic and carcinogenic health impacts through seafood product consumption. The pollution index (Pi) values of TMs in seafood products ranged from 0.01 to 0.7, with As and Cd showing the lowest and highest values, which were below 0.7, indicating their safety for consumption. The metal pollution index (MPI) for TMs in seafood ranged from 9.E-05 to 0.007, with the lowest and highest values associated with PP and TIO products. The MPI value for seafood products was below 1, signifying low TMs accumulation, suggesting the safety of seafood for consumption. The maximum seafood meal consumption limit (CRmm) was calculated, showing that adults can safely consume > 16 meals/month without chronic or acute toxicity. The results of this study suggest that the accumulation of TMs in the analyzed seafood product was below the health guidelines and pollution index values, making it suitable for smooth domestic and international export as well as safe consumption.

Transcriptome analysis of reproductive tract tissues of male river prawn Macrobrachium americanum.

BACKGROUND: The river prawn, Macrobrachium americanum (M. americanum), is one of the largest prawns of the genus in Latin America and is an amphidromous species distributed along the Pacific coast of America. This prawn has commercial value due to its size and taste, making it a good option for aquaculture production. Its culture has been attempted in ponds and concrete tanks, but no successful technique can still support commercial production. Understanding the mechanisms that regulate reproduction at the molecular level is very important. This knowledge can provide tools for manipulating transcripts, which could increase the number or size of animals in the culture. Our understanding of the mechanism that regulates the reproduction of M. americanum at the molecular level is limited. AIM: Perform and analyze the transcriptome assembly of the testes, vas deferens, and terminal ampulla of M. americanum. to provide new molecular information about its reproduction. METHODS AND RESULTS: The cDNA library was constructed and sequenced for each tissue to identify novel transcripts. A combined transcriptome with the three tissues was assembled using Trinity software. Unigenes were annotated using BLASTx and BLAST2GO. The transcriptome assembly generated 1,059,447 unigenes, of which 7222 genes had significant hits (e-value < 1 × 10-5) when compared against the Swiss-Prot database. Around 75 genes were related to sex determination, testis development, spermatogenesis, spermiogenesis, fertilization, maturation of testicular cells, neuropeptides, hormones, hormone receptors, and/or embryogenesis. CONCLUSIONS: These results provide new molecular information about M. americanum reproduction, representing a reference point for further genetic studies of this species.

Acetylcholinesterase activity in muscle tissue of Norway lobster Nephrops norvegicus: Importance of body size, season, sex and naturally occurring metals.

The aim of the present study was to determine the levels of acetylcholinesterase (AChE) activity in the tail muscle tissue of wild populations of Nephrops norvegicus from the Northern Adriatic, and correlate it to body size, seasons, sex and the content of mercury, arsenic, cadmium, lead and copper. The animals of both sexes were collected in spring and autumn from two relatively distant fishing grounds. A marked variability of muscle AChE activity was found (0.49 to 11.22 nmol/min/mg prot.), displaying the opposite seasonal trend between two sampling sites. Small, but significant negative correlation has been found between AChE activity and carapace length (rs = - 0.35, p < 0.05). Data reported here provide an essential baseline for future studies of neurotoxicity in crustaceans. The study highlights the necessity for continuous monitoring of potentially toxic metals in edible marine species to avoid possible repercussions of seafood consumption on human health.

Short-term exposure to high pCO2 leads to decreased branchial cytochrome C oxidase activity in the presence of octopamine in a decapod.

In a recent mechanistic study, octopamine was shown to promote proton transport over the branchial epithelium in green crabs, Carcinus maenas. Here, we follow up on this finding by investigating the involvement of octopamine in an environmental and physiological context that challenges acid-base homeostasis, the response to short-term high pCO2 exposure (400 Pa) in a brackish water environment. We show that hyperregulating green crabs experienced a respiratory acidosis as early as 6 h of exposure to hypercapnia, with a rise in hemolymph pCO2 accompanied by a simultaneous drop of hemolymph pH. The slightly delayed increase in hemolymph HCO3- observed after 24 h helped to restore hemolymph pH to initial values by 48 h. Circulating levels of the biogenic amine octopamine were significantly higher in short-term high pCO2 exposed crabs compared to control crabs after 48 h. Whole animal metabolic rates, intracellular levels of octopamine and cAMP, as well as branchial mitochondrial enzyme activities for complex I + III and citrate synthase were unchanged in posterior gill #7 after 48 h of hypercapnia. However, application of octopamine in gill respirometry experiments suppressed branchial metabolic rate in posterior gills of short-term high pCO2 exposed animals. Furthermore, branchial enzyme activity of cytochrome C oxidase decreased in high pCO2 exposed crabs after 48 h. Our results indicate that hyperregulating green crabs are capable of quickly counteracting a hypercapnia-induced respiratory acidosis. The role of octopamine in the acclimation of green crabs to short-term hypercapnia seems to entail the alteration of branchial metabolic pathways, possibly targeting mitochondrial cytochrome C in the gill. Our findings help advancing our current limited understanding of endocrine components in hypercapnia acclimation. SUMMARY STATEMENT: Acid-base compensation upon short-term high pCO2 exposure in hyperregulating green crabs started after 6 h and was accomplished by 48 h with the involvement of the biogenic amine octopamine, accumulation of hemolymph HCO3-, and regulation of mitochondrial complex IV (cytochrome C oxidase).

Species distribution models to predict the impacts of environmental disasters on shrimp species of economic interest.

Here, we used distribution models to predict the size of the environmentally suitable area for shrimps of fishing interest that were impacted by the tailing plume from the collapse of the Fundão Dam, one of the largest ecological disasters ever to occur in Brazil. Species distribution models (SDMs) were generated for nine species of penaeid shrimp that occurred in the impacted region. Average temperature showed the highest percentage of contribution for SDMs. The environmental suitability of penaeids varied significantly in relation to the distance to the coast and mouth river. The area of environmental suitability of shrimps impacted by tailings plumes ranged from 27 to 47 %. Notably, three protected areas displayed suitable conditions, before the disaster, for until eight species. The results obtained by the SDMs approach provide crucial information for conservation and restoration efforts of coastal biodiversity in an impacted region with limited prior knowledge about biodiversity distribution.

Assessment of microplastic contamination in shrimps from the Bay of Bengal and associated human health risk.

Microplastics (MPs) were analyzed in seven shrimp species Tiger shrimp (Penaeus monodon), Red tiger shrimp (Caridina cantonensis), Indian shrimp (Penaeus indicus), Red shrimp (Metapenaeus dobsoni), White shrimp (Penaeus merguiensis), Brown shrimp (Metapenaeus monoceros), and Roshna shrimp (Palaemon styliferus) collected from the Bay of Bengal. The abundance and characteristics of MPs were assessed in the gastrointestinal tract (GIT), which certainly translocated to the muscle of shrimp species. The highest MP abundance was found in C. cantonensis with 7.2 items/individual (25.3 items/g in the GIT and 6.3 items/g in muscle). The prominent types of MPs in shrimp samples were fibers (30 %) and fragments (29 %). The ingestion rate of MPs of black and transparent color was comparatively higher, with 64 % of the ingested MPs were < 100 µm. The primary polymer types detected based on Fourier Transform Infrared (FTIR) analysis were Low-Density Polyethylene (LDPE), High-Density Polyethylene (HDPE), Polymethyl Methacrylate (PMMA), Polyvinyl Chloride (PVC), Polypropylene (PP), and Ethylene Vinyl Acetate (EVA). Results from Scanning Electron Microscopy (SEM) showed rough surface textures and adhered particles on the MPs isolated from shrimps. The margin of exposure for females was 71.42, and for males, it was 80.64, indicating that women in Bangladesh are more likely to be exposed to MPs and face a higher risk than men. Sensitivity analysis revealed that MPs particle size was the most sensitive parameter. These findings provide a comprehensive understanding of MP ingestion, human exposure, and contamination in shrimps of Bangladesh, which can help future monitoring efforts.

Molecular docking and dynamics simulation studies uncover the host-pathogen protein-protein interactions in Penaeus vannamei and Vibrio parahaemolyticus.

Shrimp aquaculture contributes significantly to global economic growth, and the whiteleg shrimp, Penaeus vannamei, is a leading species in this industry. However, Vibrio parahaemolyticus infection poses a major challenge in ensuring the success of P. vannamei aquaculture. Despite its significance in this industry, the biological knowledge of its pathogenesis remains unclear. Hence, this study was conducted to identify the interaction sites and binding affinity between several immune-related proteins of P. vannamei with V. parahaemolyticus proteins associated with virulence factors. Potential interaction sites and the binding affinity between host and pathogen proteins were identified using molecular docking and dynamics (MD) simulation. The P. vannamei-V. parahaemolyticus protein-protein interaction of Complex 1 (Ferritin-HrpE/YscL family type III secretion apparatus protein), Complex 2 (Protein kinase domain-containing protein-Chemotaxis CheY protein), and Complex 3 (GPCR-Chemotaxis CheY protein) was found to interact with -4319.76, -5271.39, and -4725.57 of the docked score and the formation of intermolecular bonds at several interacting residues. The docked scores of Complex 1, Complex 2, and Complex 3 were validated using MD simulation analysis, which revealed these complexes greatly contribute to the interactions between P. vannamei and V. parahaemolyticus proteins, with binding free energies of -22.50 kJ/mol, -30.20 kJ/mol, and -26.27 kJ/mol, respectively. This finding illustrates the capability of computational approaches to search for molecular binding sites between host and pathogen, which could increase the knowledge of Vibrio spp. infection on shrimps, which then can be used to assist in the development of effective treatment.